Friday, February 17, 2017

Latest on Lake Oroville

This second video below is annoyingly hysterical, but it does note the work being done to avoid the water flowing back into the powerhouse.  Ignore all the fear mongering, but it does deal with this back flow issue that no one else is talking about.

My contact inside told me a week ago to watch for problems with debris and problems with water getting into the powerhouse, and here we have the first public evidence of that.  They don't want water to back up the river into the powerhouse at the base of the dam proper, as that will damage their ability to control the spillway gates, and indeed all dam operations.

The other, as for now unmentioned risk for causing water to go back up the main river channel into the powerhouse is the possibility of huge uncontrolled water releases, over either of the two spillways, which certainly would put lots of water back upstream to the base of the dam, and thus into the powerhouse.  Huge dam control problems could result if that happens, which could conceivably be as bad or worse than the loss of control of the emergency spillway.  Imagine what would happen during the spring runoff if the water gets into the powerhouse, kills all their control of the dam, and the lake runs over the dam itself.  While a very remote risk now, it is clear that the risk is not zero, that this risk has been recognized, and that efforts are now being made to plug the river between the two spillways and the powerhouse at the base of the dam.  No official comment, to my knowledge, has been made on that.

 Note as well the sloppy language when speaking of the "spillway."  There are two, the emergency spillway, and the regular, concrete spillway.  Both are separate problems.

The main spillway, which started the immediate problem by disintegrating, is currently handling the 100k out flow from the gates without further significant damage.  The water flow over this spillway is controlled.

The emergency spillway is uncontrolled.  No one directly controls flows over that except mother nature, and the incompetence of the water managers in letting the lake get too high.  Once the Feather River flows over the emergency spillway, it is a wild river.  This is where all the effort is going now, and it is all focused on the ground directly under the emergency spillway, which is just the bare earth.  All the erosion immediately threatening the control of the river is there, very understandably.  Whether these actions will help, or not, will only be known if more water goes over the emergency spillway and tests the work.

Remember, once the emergency spillway is overtopped, there is no control at all over water flows there.

Now, back to the regular concrete lined spillway.  They are now pumping all the water they dare down that, and have written off for now the lower half, which is now destroyed.  It appears that damage is not migrating up the spillway for now, and with these water flows, there is nothing at all they can do to repair it.  The real risk is that this spillway begins again to come apart, and that damage moves up the spillway toward the gates.  Then, they must stop the flows, and the river will go over the emergency spillway in huge uncontrolled flows.  There is no immediate risk of that now, because the main spillway seems stable, but the managers really cannot know if that will continue.

The main dam is not at any risk now.  There is a risk to the powerhouse and the controls of the dam, which sit at the base.  No one is really speaking about that publicly, but they clearly are taking action to keep the water out.

So, in summary, three things to be concerned about.  The emergency spillway first and immediately.  Second, you can bet your bottom dollar that they are watching the main spillway with huge concern, but for now, that problem is stable. Finally, they must keep the debris from all this from backing water into the powerhouse, and now have applied huge earthmovers to do just that.  Watch for that to bubble up in the next few weeks as a problem if they manage to keep water from going over the emergency spillway again.

So there you have it.  I'd hate to live in Oroville right now.  Even if they solve all these problems, and they get through the spring runoff with no disaster, the property values in little Oroville are going to crater.


  1. What's the news about money being put into the Folsom dam instead of the Oroville dam? I heard something about that but didn't know if it was accurate.

    1. Dunno yet, but it seems the dam at Folsom is handling the water flow quite well.

    2. saw this:
      and it makes me really mad that the damn bullet train is still on this list. Billions of wasted infrastructure dollars!

  2. Why is the powerhouse at the base of the dam where it could be flooded? Just asking..............

    1. I'm just speculating, but first, it's because they use "head" or the length of the fall of water, to generate energy at the turbines, and thus electricity. The higher the head, the more energy created by the fall of the water, and the easier it is to generate more electricity. Hence, the best location is at the base.
      Second, there is the chance of water backing up into the powerhouse, but the people who design these big dams like to think that they have considered all the scenarios where that can happen, and design that possibility away. It would take an extraordinary combination of events, so strange to the logical minds of the architects and water managers, to cause a significant water backup into the powerhouse, that it is just about impossible. Looks like the situation at Oroville Dam is going to prove that it is in fact possible with the right combination of sudden natural events and human incompetence stretching over decades.

  3. Thanks. I didn't realize that the powerhouse contained turbines. I thought that it was just more of a control room and the power came from somewhere else. Now it makes sense.............

  4. As a note about the Fulsom dam and reservoir, in the 80s the greens sued the Corps of Engineers to stop dredging the reservoir, so now decades later it holds a significantly smaller amount of water than it could.

    Also, SMUD, wanted to build a series of dams north east of Placervulle in steep, narrow valleys where no one could build cabins or live but was shut out by the greens. CW may remember that battle because he lives nearby.

    In typical Californian insanity, along Highway 50 east of Sacramento, developers built a dry subdivision because there wasn't enough ground water to support the subdivision. Everyone agreed it was going to be dry, but now three decades later the courts ordered that subdivision onto city water because the residents were tired of purchasing and hauling their own water as originally agreed upon.


  5. The bigger problem I can see was the original design having the emergency spillway dump straight on to bare earth, no armoring.... That is a design you would expect to undermine the emergency spillway if you ever had to use it, and a long use would end up dumping 30-odd feet of retention lake catastrophically when the emergency spillway finally failed.

    If they had included a concrete pan out 30-40 feet we would be focusing on the major failure on the regular spillway